1. Field of the Invention
The present invention relates to a peeling jig for a bonded wafer, and more specifically to a peeling jig suitable for use in separating bonded wafer having voids which have occurred, prior to thermal process in the fabrication of bonded SOI wafers.
2. Description of the Prior Art
Referring to FIG. 3, in a conventional method for fabricating a bonded SOI wafer, a single-side mirror processed supporting substrate 3 and an active wafer 4, which has been single-side mirror processed and thermal oxidation processed to form an insulating layer 4b (SiO.sub.2) of a predetermined thickness, are respectively hydrophilic processed by means of ammonia and hydrogen peroxide solution or the like, followed by bonding them together using bonding jigs. The bonded wafers are then thermally processed to finish the bonding process.
Even if there is only one void found in a bonded wafer, the bonded wafer is discarded as a defective item or the bonding surface thereof is peeled with a peeling jig and then rebonded.
However, once the bonded wafer is peeled off from its bonding surface into a supporting substrate(wafer) and an active wafer, scars are formed at the bonding surfaces thereof when the bonding surfaces are in contact with the peeling jig, or particles are adhered thereon, making the wafers unsuitable for reuse. Therefore, it is a disadvantage that the wafers which have scars or the wafers on which particles are adhered that can not be washed off must be discarded.
Not only bonded SOI wafer but direct bonded wafers which have not insulating layers sandwiched between the supporting substrate and the active wafer, have a similar disadvantage.